From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-3.3 required=3.0 tests=BAYES_00, BUG6152_INVALID_DATE_TZ_ABSURD,DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU, HEADER_FROM_DIFFERENT_DOMAINS,INVALID_DATE_TZ_ABSURD,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 14B7CC433DF for ; Wed, 26 Aug 2020 08:39:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id DBA2B20707 for ; Wed, 26 Aug 2020 08:39:08 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="JtLWwenJ"; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="OFqmKblX" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727111AbgHZIjH (ORCPT ); Wed, 26 Aug 2020 04:39:07 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60652 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727030AbgHZIjG (ORCPT ); Wed, 26 Aug 2020 04:39:06 -0400 Received: from galois.linutronix.de (Galois.linutronix.de [IPv6:2a0a:51c0:0:12e:550::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id AF964C061574 for ; Wed, 26 Aug 2020 01:39:06 -0700 (PDT) From: John Ogness DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1598431144; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=ioAxhFzpgilIVQ5B/okT+TPEavcUfC9KtYUnzhhh+Ks=; b=JtLWwenJ18uKrMm4N/jo2ul6kSyZwObGCDwv6DwIwVEg7usFORbY1SjARm/j14RLqB4b+q S8GvBbN798/cmEebuV2eZ2526CKgVDob4AOKc1zmc90C212141gw8/sg1Dwh72Z4ZtTUaj 1j0qg/+J68dno8tdo2E2FF3zAUj+DUEsp2gS/bAZdMKu/01oXYnB1oQcs5i5nxWKzUTDGl P2SVW6g0fr9f3rFRyFfL7Uh+3iwdARSDGBb2dWzlq/BBZ/W/QZsBeJ1J6YEIbc/JRCeaXh UeNOifnXQx143BOjaDCPHiJFU6WcSd1Hxs1CeUsXras0X2+q2MO4REN4rsoSjg== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1598431144; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=ioAxhFzpgilIVQ5B/okT+TPEavcUfC9KtYUnzhhh+Ks=; b=OFqmKblXPVRfXFuD9xS0kEtUZOoRkr07eTSRqcDIwu7oQ5a2O7LkRSmNJgMrOf180ux/bY jMw+8wWqEZANCzCg== To: Petr Mladek Cc: Sergey Senozhatsky , Sergey Senozhatsky , Steven Rostedt , Linus Torvalds , Greg Kroah-Hartman , Thomas Gleixner , Peter Zijlstra , Andrea Parri , Paul McKenney , kexec@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2 5/7][next] printk: ringbuffer: add finalization/extension support In-Reply-To: <20200824103538.31446-6-john.ogness@linutronix.de> References: <20200824103538.31446-1-john.ogness@linutronix.de> <20200824103538.31446-6-john.ogness@linutronix.de> Date: Wed, 26 Aug 2020 10:45:03 +0206 Message-ID: <87lfi1ls2g.fsf@jogness.linutronix.de> MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2020-08-24, John Ogness wrote: > @@ -1157,6 +1431,14 @@ bool prb_reserve(struct prb_reserved_entry *e, struct printk_ringbuffer *rb, > goto fail; > } > > + /* > + * New data is about to be reserved. Once that happens, previous > + * descriptors are no longer able to be extended. Finalize the > + * previous descriptor now so that it can be made available to > + * readers (when committed). > + */ > + desc_finalize(desc_ring, DESC_ID(id - 1)); > + > d = to_desc(desc_ring, id); > > /* Apparently this is not enough to guarantee that past descriptors are finalized. I am able to reproduce a scenario where the finalization of a certain descriptor never happens. That leaves the descriptor permanently in the reserved queried state, which prevents any new records from being created. I am investigating. John Ogness